This invention relates to a swivel adaptor employed in association with an inlet pipe leading to a storage tank. The adaptor has particular application to inlet pipes associated with underground storage tanks, for example those employed to store gasoline or other liquid fuels.
U.S. Pat. No. 5,664,951, issued Sep. 9, 1997, discloses a swivel adaptor for an inlet conduit or pipe leading to an underground storage tank for gasoline. Such underground storage tanks are typically filled from a hose associated with a tanker truck, the hose being mechanically connected to an inlet of the pipe leading to the underground tank. Connection is usually established through use of an adaptor secured to the inlet pipe and mechanically connected in some fashion to the hose.
Prior art inlet conduit adaptors of the conventional type have been plagued by the loss of sealing relationship in the interface between the hose and the inlet conduit. Gasoline and/or vapor leakage will occur at the interface when there is a sealing loss.
Sealing loss is often caused by relative rotation occurring between the various components providing the interconnection or interface. Adaptors designed for fixed attachment to the inlet pipe can have substantial torque applied thereto during the course of applying and utilizing the hose and cause the adaptor to rotate relative to the inlet conduit, in turn causing leakage.
U.S. Pat. No. 5,664,951 discloses an approach aimed at solving this problem. More particularly, a swivel adaptor is disclosed in the patent including two relatively movable components. The components are formed of electrically conductive material and are held together by an electrically conductive flexible rod located between the first and second adaptor components. The flexible rod prevents relative axial movement between the adaptor components but allows relative rotational movement therebetween in the event torque is applied to the adaptor, for example by a hose. Seals are provided between the relatively movable adaptor components to prevent or limit fluid leakage between the two adaptor components. The band employed in the arrangement of U.S. Pat. No. 5,664,951 provides an electrical connection between the first and second components for preventing the build-up of static electricity between those components.
Use of a band such as that employed in the device of U.S. Pat. No. 5,664,951 has a number of disadvantages. For example, the band can wear out and come apart over time. This not only is detrimental to the stability of the adaptor but also can result in separation of the adaptor components when substantial forces are applied thereto and band wear is significant. Furthermore, wearing of the band can impair its ability to conduct electricity between the relatively rotatable adaptor components.
The present invention relates to an improved swivel adaptor which incorporates features aimed at reducing wear of the adaptor components and also ensuring maintenance of an electrical connection between the relatively rotatable members of the swivel adaptor.
The swivel adaptor of the present invention is for connection to an inlet pipe leading to a storage tank.
The swivel adaptor includes a first swivel adaptor member for attachment to an inlet pipe leading to a storage tank, the first swivel adaptor member defining a liquid passageway. The first swivel adaptor member is electrically conductive and includes a first swivel adaptor member peripheral surface concentrically disposed about an axis and having a first swivel adaptor member ball bearing retention groove.
The adaptor also includes a second swivel adaptor member which is rotatably mounted on the first swivel adaptor member. The second swivel adaptor member has an inlet leading to the first swivel adaptor member liquid passageway. The second swivel adaptor member is also electrically conductive and includes a second swivel adaptor peripheral surface concentrically disposed about the axis adjacent to the first swivel adaptor member peripheral wall and having a second swivel adaptor member ball bearing retention groove.
The first swivel adaptor member ball bearing retention groove and the second swivel adaptor member ball bearing retention groove are in substantial registry and define a circular channel concentrically disposed about the axis.
A plurality of electrically conductive ball bearings are positioned in the channel, the ball bearings allowing ready rotation of the second swivel adaptor member relative to the first swivel adaptor member about the axis, preventing separation of the first swivel adaptor member and the second swivel adaptor member and providing an electrical interconnection between the first swivel adaptor member and the second swivel adaptor member.